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#include "libm.h" // for ldshape, ldshape::(anonymous), FORCE_EVAL

#include <float.h>  // for LDBL_MANT_DIG, LDBL_MAX_EXP
#include <math.h>   // for expl, coshl, expm1l
#include <stdint.h> // for uint32_t

#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double coshl(long double x)
{
	return cosh(x);
}
#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
long double coshl(long double x)
{
	union ldshape u = { x };
	unsigned ex = u.i.se & 0x7fff;
	uint32_t w;
	long double t;

	/* |x| */
	u.i.se = ex;
	x = u.f;
	w = u.i.m >> 32;

	/* |x| < log(2) */
	if (ex < 0x3fff - 1 || (ex == 0x3fff - 1 && w < 0xb17217f7)) {
		if (ex < 0x3fff - 32) {
			FORCE_EVAL(x + 0x1p120f);
			return 1;
		}
		t = expm1l(x);
		return 1 + t * t / (2 * (1 + t));
	}

	/* |x| < log(LDBL_MAX) */
	if (ex < 0x3fff + 13 || (ex == 0x3fff + 13 && w < 0xb17217f7)) {
		t = expl(x);
		return 0.5 * (t + 1 / t);
	}

	/* |x| > log(LDBL_MAX) or nan */
	t = expl(0.5 * x);
	return 0.5 * t * t;
}
#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
// TODO: broken implementation to make things compile
long double coshl(long double x)
{
	return cosh(x);
}
#endif